The Forever War, by Joe Haldeman ISBN 0380708213
Five out of five stars
This novel strongly appeals to my taste in science fiction, where the personal and social consequences of major events are examined and projected. The Earth is locked in an interstellar war with the Taurans and the most talented are drafted into the military, taken from Earth with no possibility of deferment. This story follows the military career of William Mandella.
The battles take place on all types of planets, so the bulk of their training takes place on Charon, the moon of Pluto. With the temperature only a few degrees above absolute zero, the slightest misstep leads to death, so the casualty rate in training is very high. In battle it is even higher.
While the ships are capable of interstellar flight, there is no faster than light travel, although the velocity is fast enough for significant time dilation. A one year (subjective) tour of duty is often decades of elapsed time in reality. Therefore, soldiers on leave on Earth face a society that they no longer fit into. They even have difficulty understanding the language and Earth is so crowded that there are battles over the food in small garden plots.
One aspect of the story that I found appealing is the one-sided change in military technology between battles when the long distances are factored in. A battle takes place on one planet with the humans winning. The human resources are marshalled and then sent to the next battle, but the distance means that the enemy has had many years to prepare new tactics and equipment while the humans had only a few months. When one considers that the warplanes that did so well at the start of World War II were hopelessly outperformed by the end six years later, it is clear that winning two such battles in a row is very difficult.
This is a great story about how the society that a soldier is fighting to defend will often be replaced while he is fighting. Haldeman engages in some logical extrapolations where the population problem on Earth is solved by the development of a new norm in sexual activity. He also develops a plausible consequence of humans fighting an interstellar war when there is no faster than light travel, only time dilation and massive changes while the soldiers experience only a few months.